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Down but not out: These large-cap stocks have been crushed in 2015, but they could be a major bargain for long-term investors.

Following four years without a correction in the stock market, investors were awakened to a new reality in August: Stocks can actually go down, too!

As a whole, it's been a pretty rough year for some of the markets' largest stocks. Of the roughly 600 companies with a market valuation of $10 billion or more (i.e., large-cap stocks), just 270 have moved higher year to date. On the flipside, almost a full third of large-cap stocks are down 10% or more year to date. Short-term traders might use this correction as a reason to retreat to the hills, but smart long-term investors understand that a drop in the share price of high-quality stocks represents a potential buying opportunity.

These large caps have been pummeled With this in mind, I propose to take a look at some of the worst large-cap performers year to date to uncover the select few stocks that look ripe for a potential rebound. As a general reminder, the opinions expressed here are my own, and you should consider any discussion of the following large-cap stocks as a jumping-off point for your own research rather than a concrete recommendation to buy.

Without further ado, I believe you'd be wise to keep these beaten-down large-cap stocks on your radar:

Source: Whole Foods Market.

Whole Foods Market(NASDAQ:WFM): down 34% year to dateWhole Foods may offer healthful organic and natural products for us to consume, but its shares have been anything but "healthful" in 2015. In Whole Foods' most recent quarterly report it recorded $3.63 billion in sales, $0.41 per share in EPS, and 1.3% growth in comparable-store sales. Comparatively, Wall Street was anticipating $3.69 billion in sales, $0.43 in EPS, and 2.9% in same-store sales growth. The miss caused Wall Street to pounce on Whole Foods.

Though I'm not going to defend the miss, I am going to suggest that Whole Foods has the tools and strategy needed to right the ship.

For starters, Whole Foods is attempting to appeal to younger shoppers with its newly introduced "365" stores. After observing Wal-Mart's success in opening its smaller Express locations, Whole Foods is carefully choosing a product mix in its smaller stores that'll help it appeal to cost-conscious millennials who are seeking healthier food options. Small stores tend to hit home in smaller towns where mom-and-pop shops dominate, and they could continue to give Whole Foods a more personal feel than larger-chain grocers.

To boot, Whole Foods also has a considerably larger supply chain than its organic grocery rivals. Bigger isn't always better when it comes to retail, but having a vast network of stores affords Whole Foods the ability to negotiate prices and pull cost-reducing levers that some of its organic food rivals may not have.

Sporting a PEG ratio of 1.7 and a 1.6% dividend yield, Whole Foods has modest upside potential that could appeal to long-term investors.

Source: National Oilwell Varco.

National Oilwell Varco(NYSE:NOV): down 38% year to dateOil equipment and services supplier National Oilwell Varco has been absolutely hammered this year on the heels of the precipitous decline in oil prices and U.S. drilling rig counts.

As Foolish energy guru Tyler Crowe pointed out recently, National Oilwell Varco's Rig Systems' business typically accounts for up to half its revenue and up to three-quarters of its operating income. However, with little to no demand for new rigs with West Texas Intermediate crude staying below $50 per barrel, National Oilwell Varco's backlog has suffered.

Over the long run, though, there could be opportunity to be had in this decline. Specifically, the oil and gas boom is still in its early stages, at least within the United States. Even abroad, such as in Africa (onshore and offshore), the outlook strongly suggests that new rig demand, or even replacement equipment demand for existing rigs, should be strong over the long run. Oil naturally cycles up and down over time, so investors that approach National Oilwell Varco with a long-term mind-set should be rewarded.

Global energy demand is also on the rise. By 2040, the Energy Information Administration predicts that global energy demand will have jumped by 37%. Within the U.S., drillers have boosted production despite halving rig counts – but this can only continue for so long. At some point in the future demand is going to outstrip supply and National Oilwell's backlog should be booming once again. Keep in mind that there aren't concerns about National Oilwell's profitability at this point (it's expected to stay healthfully profitable), so it just appears to be a matter of riding out the storm.

Following the tumble, and with the support of a currently market-topping dividend yield, National Oilwell Varco could be a bargain.

Source: Flickr user Rachel Johnson.

Baidu(NASDAQ:BIDU): down 35% year to date Keeping with the theme, China's search engine behemoth Baidu has tumbled more than $80 per share for the year after announcing weaker-than-expected top- and bottom-line guidance on the heels of beefed up spending in newer business platforms. Baidu intends to spend heavily to make its imprint in online-to-offline (O2O) transactions, such as groceries or movie tickets, which could allow it to become a mobile revenue-generating giant. Unfortunately, Baidu's margins are taking a hit in the meantime, and its shareholders are clearly not thrilled.

Still, there are reasons to believe that this decline in Baidu's stock price could be short-lived. For example, Baidu remains the undisputed kingpin in search in China. According to EnfoDesk, at the end of 2014 Baidu maintained 79.5% of search engine market share in China. Furthermore, search has grown between 37% and 67% in China in each of the past six years. As long as Baidu remains the top dog among search, it'll continue to generate juicy margins and ample revenue from advertisers.

Also, investors have to consider that its O2O play is a long-tail success opportunity. Facebook didn't flip a switch and become a monster at mobile, and neither will Baidu with its attempt to dominate O2O. However, even with just single-digit market share in O2O, Baidu witnessed its gross merchandise volume soar 109% to $6.5 billion in Q2. Baidu certainly has a chance to become the dominant mobile force in China.

With growth expected to remain well in excess of 25% per year for the foreseeable future, Baidu looks inexpensive in this investor's eyes.

Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

John Mackey, co-CEO of Whole Foods Market, is a member of The Motley Fool's board of directors. The Motley Fool owns and recommends Baidu, Facebook, National Oilwell Varco, and Whole Foods Market. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

Author

A Fool since 2010, and a graduate from UC San Diego with a B.A. in Economics, Sean specializes in the healthcare sector and investment planning. You'll often find him writing about Obamacare, marijuana, drug and device development, Social Security, taxes, retirement issues and general macroeconomic topics of interest. Follow @TMFUltraLong